1. Field of the Invention
The present invention relates to a color-sensitive radiation composition, a color filter having a color pattern formed using the color-sensitive radiation composition, a method for producing a color pattern, furthermore, a solid-state imaging device using the color filter, and a liquid crystal display apparatus.
2. Description of the Related Art
Recently, in accordance with the development of personal computers, in particular, large-screen liquid crystal televisions, liquid crystal displays (LCD), in particular, color liquid crystal displays have tended to be in increased demand. In accordance with the demand for higher image qualities, predominance of organic EL displays is required. Meanwhile, as digital cameras, camera-mounted mobile phones are predominant, and solid-state imaging devices such as CCD image sensors are also being rapidly developed.
Color filters are used as key devices of displays or imaging devices, and the demand for higher quality and cost reduction is increasing. A color filter commonly includes color patterns with three colors of red (R), green (G), and blue (B) and divides light that passes through displays or imaging devices into three colors.
Coloring agents used for color filters require the following characteristics in common. That is, coloring agents should have spectral characteristics that are desirable in terms of color reproduction, be free from optical disorders such as light scattering that causes deterioration in contrast of liquid crystal displays and non-uniform optical concentration that causes color unevenness in solid-state imaging devices, have superior resistance such as heat resistance, light resistance and moisture resistance under environmental conditions, and have a high molar extinction coefficient and ability to be formed into thin films. For this reason, a pigment is generally used as a coloring agent.
Recently, higher accuracy of color filters for solid-state imaging devices has been required.
However, it is difficult to further improve resolution of a means using a pigment as a conventional coloring agent, since color unevenness is caused by coarse particles of the pigment. In addition, when a pigment is used as a coloring agent with respect to liquid crystal displays, the manufactured liquid crystal displays exhibit superior light resistance or heat resistance, but have a problem in which contrast is deteriorated or haze is increased in order to realize light scattering by pigment particles.
For this reason, use of dyes other than pigments as coloring agents may be considered. When a dye is used as a coloring agent, color filters for solid-state imaging devices solve the problem of color unevenness, thus accomplishing high resolution. In color filters for liquid crystal displays or organic EL displays, improvement in optical properties such as contrast or haze is expected.
Under the aforementioned circumstances, use of dyes as coloring agents is considered. (For example, see JP-1994-75375A (JP-H6-75375A)). However, disadvantageously, a curable composition containing a dye generally has lower light resistance or heat resistance than a pigment and tends to inhibit radical polymerization reaction, has a low solubility in an alkali aqueous solution or an organic solvent (hereinafter, also referred to simply as a solvent), thus making it difficult to obtain a curable composition having a desired spectrum, and often exhibits interactions with other components, thus making it difficult to control solubility of uncured parts (development property). For this reason, formation of thin films and color patterns of color filters with superior resistance at a high accuracy using a dye has been difficult to date.
Regarding such problems, a variety of methods such as selection of the type of conventional initiators or increase of added amount of initiators are suggested (for example, see JP-2005-316012A).
Also, focusing on spectral characteristics suitable for color filters, a radiation-sensitive colored composition and a dye compound using a dipyrromethane dye is considered (for example, see JP-2008-292970A).
Also, to solve problems associated with a sublimation property in production of color filters, a color filter containing a polymer having a triphenylmethane dye in the molecule as a coloring agent is suggested (for example, see JP-3736221B).